Ports and Adapters (Hexagonal Architecture)

The Ports and Adapters architecture, also known as Hexagonal architecture, is a domain-centric architecture that allows applications to be isolated from external concerns. This architecture was first introduced by Alistair Cockburn in 1994 and later written about in his blog in 2005. The main intention of this architecture is to enable an application to be driven by various users, programs, and scripts, while being developed and tested in isolation from its runtime devices and databases. The business logic is the core of the application and should be protected and isolated from external dependencies. The Ports and Adapters architecture achieves this by decoupling the business logic from external factors, making it easily replaceable and maintainable. The architecture is use-case-driven, where the focus is on the use cases and not on the implementation details such as the database or other external factors. The hexagon in the architecture represents the core business logic, with ports and adapters acting as interfaces to interact with the outside world. Ports are defined by the hexagon and implemented by adapters outside the hexagon, allowing for communication between the application and external actors. The adapters act as middle elements between the actors and the ports, converting data to make it compatible with the application or external actors. By using the Ports and Adapters architecture, developers can build resilient and adaptable software that can evolve independently of external factors.